Today, diagnoses by medical imaging are accomplished by displaying object organs such as blood vessels and bronchus in three-dimensional medical images obtained from a medical imaging apparatus and reading the displayed images of the three-dimensional medical images with respect to any matter sticking to the organs or the like. The matter sticking in this context may be plaques, thrombi, polyps or calcification. For instance, Patent Document 1 discloses a technique to display a curved tomogram along the center line of an object organ to enable the interior of the object organ to be observed. This displaying technique visualizes density information of a tomogram along the center line linking the centers of the area farther inside than the inner wall of the object organ. This visualization makes possible the following image diagnoses of the object organ. These image diagnoses make possible, for instance, measurement of the blood vessel diameter and the degree of its stricture and the discovery of a polyp in the large intestine without using an intestinal camera.
Patent Document 1: Japanese Patent Application Laid-Open No. 11-318884
According to Patent Document 1, since tomograms along the center line of an object organ are obtained, displaying of a single tomogram enables only the presence of any matter sticking to an object organ to be recognized. Therefore, in order for a physician to confirm the state of the disease due to sticking matter and to plan the policy of therapy, he has to obtain a plurality of tomograms, display them in the sequence of their being picked up and observe how extensively the stuck matter is spread over the object organ. Preparation of the plurality of tomograms requires setting of complex parameters for each individual tomogram. Moreover, in this diagnosis by the doctor, the doctor reads the prepared plurality of tomograms, estimates the spread of the stuck matter over the object organ relying on his own anatomical knowledge, and gives a diagnosis. Thus, Patent Document 1 reflects no consideration for the possibility to enable the state of the sticking matter to the object organ to be observed at a glance.